Making mods is not trivial, a huge mod like this one is a giant undertaking even if he didn't himself produce everything. Sounds like credit was given though, he thanked just about anyone and everyone for contributing and allowing him to get this job. This is not trivial, he's a 19 year old who landed an awesome gig due to hard work. For the naysayers, try and do the same thing, you'll find out it's very difficult to break in.